The Planet of Unusually Tall Things

The television series opens on this planet, and it appears in the first scene of the pilot episode "Sidekicked". It seems to be an Earth-like planet, but with numerous cliff-like geological features, extending up into outer space.

Earthworm Jim and Peter Puppy were left hanging off a cliff here by Professor Monkey-For-A-Head, who hunted them in a massive mecha. Jim was able to defeat the mad Professor by detaching the hand of his Super Suit, which floated off and punched the Professor out. However, after flying off to safety on the Pocket Rocket, Jim accidentally stepped on Peter's foot, causing a monstrous transformation, and Peter mauled Jim's Super Suit.